From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [59.151.112.132] (helo=heian.cn.fujitsu.com) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1Z1tyn-0004zz-SC for linux-mtd@lists.infradead.org; Mon, 08 Jun 2015 10:08:30 +0000 Message-ID: <55756867.1040403@cn.fujitsu.com> Date: Mon, 8 Jun 2015 18:03:19 +0800 From: Dongsheng Yang MIME-Version: 1.0 To: Richard Weinberger , , Subject: Re: [PATCH] ubifs: Introduce a mount option of force_atime. References: <1433752038-17276-1-git-send-email-yangds.fnst@cn.fujitsu.com> <557555F6.4030009@nod.at> <55755C48.4080802@cn.fujitsu.com> <5575616C.5090504@nod.at> <55756665.5070805@cn.fujitsu.com> <5575681D.20905@nod.at> In-Reply-To: <5575681D.20905@nod.at> Content-Type: text/plain; charset="ISO-8859-15"; format=flowed Content-Transfer-Encoding: 7bit Cc: linux-mtd@lists.infradead.org List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 06/08/2015 06:02 PM, Richard Weinberger wrote: > Am 08.06.2015 um 11:54 schrieb Dongsheng Yang: >> On 06/08/2015 05:33 PM, Richard Weinberger wrote: >>> Am 08.06.2015 um 11:11 schrieb Dongsheng Yang: >>>> On 06/08/2015 04:44 PM, Richard Weinberger wrote: >>>>> Am 08.06.2015 um 10:27 schrieb Dongsheng Yang: >>>>>> Currently, ubifs does not support access time anyway. I understand >>>>>> that there is a overhead to update inode in each access from user. >>>>>> >>>>>> But for the following two reasons, I think we can make it optional >>>>>> to user. >>>>>> >>>>>> (1). More and more flash storage in server are trying to use ubifs, >>>>>> it is not only for a device such as mobile phone any more, we want >>>>>> to use it in more and more generic way. Then we need to compete >>>>>> with some other main filesystems. From this point, access time is >>>>>> necessary to us, at least as a choice to user currently. >>>>> >>>>> Do you have a reference? I know that modern servers use a lot of SSDs >>>>> which use internally NAND (mostly MLC and TLC). >>>>> But which systems use RAW NAND where they would care about the atime? >>>> >>>> Hi Richard, >>>> >>>> Thanx for your quick response here. >>>> >>>> http://www.slideshare.net/FujitsuTS/bos-c113a-data-will-change-business-but-will-it-really-change-ict >>>> I am not sure is that url available to you. But that's what my team is >>>> focus on. It's about a server-using NAND device. >>> >>> So, you want to use UBI/UBIFS on NAND attached via PCEe? >>> Is this SLC NAND? (UBI and UBIFS was designed with SLC in mind). >>> MLC and TLC are a major challenge for UBI/UBIFS. >> >> It's SLC. > > Where can i get one of those? ;-) Haha, unfortunately, it's a research project in Fujitsu lab. There is a client, I am sorry I can't share the customer company name of it, for this device. But I am afraid others would have to wait a long time to get it in the market. :) > > Thanks, > //richard > . >